Electromagnetic relay with an interchangeable contact mechanism



G. A. JELLEY Aug. 24, 1965 ELECTROMAGNETIC RELAY WITH AN INTERCHANGEABLE CONTACT MECHANISM 5 Sheets-Sheet 1 Filed March 6, 1961 mmm R m Q NM Q Q Q N 3 M Q m S 5 @m N 5 M 3 Inventor A Home G. A. JELLEY Aug. 24, 1965 ELECTROMAGNETIC RELAY WITH AN INTERCHANGEABLE CONTACT MECHANISM Filed March 6, 1961 5 Sheets-Sheet 2 G. A. JELLEY Aug. 24, 1965 ELECTROMAGNETIC RELAY WITH AN INTERCHANGEABLE CONTACT MECHANISM 5 Sheets-Sheet 3 Filed March 6, 1961 United States Patent company Filed Mar. 6, H61, Ser. No. 93,518 Claims priority, application Great Britain, Mar. 10, 1960,

9 Claims. (Cl- 200-104) This invention relates to Inultipole electric relays of the kind in which an armature'is adapted to be displaced under the control of a coil and an associated magnet to actuate a carrier having moving contacts which are engageable with fixed contacts.

The object of the present invention is to provide a relay of simple and compact construction, which is capable of operating efliciently whether it comprises either normally open and normally closed contacts, or normally open contacts only. In accordance with the said invention, the contact carrier of a relay of the kind referred to is provided with contacts movable between fixed contacts on an arc chamber and fixed contacts on a detachable member which imposes a predetermined load upon the carrier and is replaceable by means adapted to impose a corresponding or substantially identical force on the said carrier so as to enable a normally open and a normally closed contact arrangement to be substtiuted by a normally open contact arrangement only without having to install a diiferent coil.

In order that the invention may be more readily understood and carried into practice, reference will now be made to the accompanyingdrawings wherein:

FIGURE 1 is an elevation, partly in section, of an electric relay provided with an upper system of normally closed, and a lower system of normally open, contacts.

FIGURE 2 is a section along the line lI-II, FIG- URE 1.

FIGURE 3 is a partly exploded perspective view of a relay and amounting plate {and FIGURE 4 is a perspective view of a bowed spring means used as a substitute for the head shown in FIGS. 1-3.

Referring to the drawings, the relay comprises a boxlike base or body portion 1, an arc chamber 2 which is superimposed upon and spans the mouth of the base, and a head member 3 which is superimposed upon the arc chamber, the said base, are chamber and head member each consisting of a moulding of electric insulating material and all being of the same width.

A rectangular and substantially flat attachment plate 4, is secured to the underside of the base by screws 5; the plate is of the same width as, but of greater length than, the moulded base and projects (see FIGURES 2 and 3) equidistantly beyond the opposite ends of the said base; the said attachment plate is formed with a key-hole shaped opening 6 in the vicinity of one corner of one of its projecting portions, and with a slot 7 in the diagonally opposed corner of its other projecting portion, as shown in FIG. 3; the said slot reaches and opens to the transverse edge of the adjacent plate end.

The presence of the attachment plate on the underside of the base 1, enables the relay to be mounted upon a channel shaped metal back plate 8 which is of a width in excess of twice the width of the base 1; the channel extends across the width of the back plate and has a flat base or floor 9 and outwardly extending flanges 16 along the free edges of its side walls 11. The fiat floor enables the back plate to be secured upon a panel or support (not shown) and the flanges provide means whereby two relays ice may be detachably mounted, side-by-side, upon the said plate by passing the key-hole opening in each of the respective attachment plates over the head of a screw (not shown) engaging a corresponding one of two tapped holes 12 in one of the flanges 10 and by passing the slot 7 in each of the said attachment plates into engagement with the shank of a screw (not shown) engaging a corresponding one of two tapped holes 13 in the other of the said flanges; as a consequence, each attachment plate spans the mouth, and is spaced from the floor, of the back plate; also, since the holed and slotted portions of the attachment plates project respectively beyond the opposite ends of the relay bases, the heads of the said screws are exposed and are accessible by a screwdriver so that the screws may be tightened to secure both relays firmly upon the back plate 8 and, when desired, slackened to enable the relays to be readily lifted and removed from the said plate.

The box-like base 1 of the relay houses a shallow E- shaped magnet 14 of which the bridge 14* seats upon a bow spring 15 disposed in a transverse groove 16 in the bottom of the base. The former 17 of a coil 18 has an axial bore 19 of rectangular section and the central limb 14 of the said magnet is of a corresponding but smaller section and is received within one end of the said bore; the coil is disposed between outwardly extending peripheral flanges 26, 21, onthe opposite ends of the former 17, the flange 20 being seated upon the magnet between the central limb 14 and two outer limbs 14, whereas the flange 21 enters an opposed pair of recesses 22 formed in the rim of the base, and is clamped in the said recesses by the rim of the superimposed arc chamber 2.

The are chamber is also of box-like formation, and is secured mouth downwards upon the base 1 by screws 23 which pass freely through straps 24, moulded integrally with and externally of the chamber, and which engage tapped bushes 25 secured within lugs 26 moulded on and externally of the base 1. The are chamber is also formed with a system of external and parallel ribs or partitions 27 which project from the end walls and crown of the chamber, and each strap 24 is located between a corresponding two of the said partitions at the mouth of the chamber.

A contact carrier 28 which also consists of a moulding of electric insulating material is slidably housed within the arc chamber and is secured upon the bridge 29 of an E-shaped armature 29 of which the central limb 29* extends into the other end of the bore of the coil former 17 and the outer limbs 29 embrace the coil and former, are in respective alignment with the outer limbs 14 of the shallow magnet 14, and are formed with lateral ribs 29 which are received and are slidable lengthwise of internal guiding grooves l in the walls of the base 1. Between each two adjacent partitions 27, the chamber is formed with an opposed pair of external lugs 30 which are located adjacent and at opposite ends of the chamber crown; each lug 30 has a corresponding one of a pair of fixed contacts 31 secured thereto by a threaded terminal post 32, the said contacts reaching over the crown of the chamber to the opposite edges of an opening 33 formed in and transversely of the said crown and extending from one to the other side wall of the chamber.

Each of the partitions 27 located between the said side walls has a slot 34 which extends between its upper edge and the opening 33, the said slots coinciding one with another transversely of the chamber 2 to form a transverse gap,'and a traverse 23 see FIG. 4, forming part of the contact carrier 23 projects through the opening 33 into the said gap; between each two adjacent partitions, the said traverse is formed with an aperture 28 in which a pair of channel-section metal pressings 35 are accommodated mouth-to-mouth. A compressed coil spring 36 interposed between the pressings of each pair, urges them apart towards and away from the base 1 respectively and a central depression 35* is formed in the external surface of the base of each of the said pressings. The apertures 28' alternate, transversely of the contact carrier, with ribs 23 (see FIGURE 3) which project from opposite sides of the traverse and engage freely in guiding grooves 27 in the edges of the partitions on opposite sides of the said gap.

'A metal strip 37 formed with a central nose 37, passes between each pressing 35 and one edge of the corresponding aperture 28 the said strip being held against longitudinal movement by engagement of the nose $7 with the depression in the base of the pressing, and being provided at its opposite ends with a lower pair of moving contact buttons 38 which are adapted respectively to be taken into and out of abutment with the fixed contacts 31 to provide one of a lower system of a set of normally open contacts. similar contact strip 39 formed with a central nose 39 which engages the depression in the base of the corresponding pressing remote from the base, and provided at each of its opposite ends with a moving contact button 40, also passes through each of the traverse apertures 28 The moving contact buttons 40 of each strip 3! are adapted to be taken into and out of abutment with a corresponding pair of fixed contacts 41 to provide one of a set of an upper system of normally closed contacts.

The fixed contacts 41 are mounted upon the head member 3 which comprises an inverted T-section body 3 and is formed with partitions 42 each of which is located in the same plane as a corresponding one of the chamber partitions 27; each of the said fixed contacts 41 is accommodated between a corresponding two of the partitions 42 and embraces one or other of the ends of the head of the body 3 to which it is secured by a threaded terminal post 43 screwed into the said head.

normally closed set engage their complemntary fixed contacts before the plunger-initiated return movement of the said assembly is completed so that during the final stage of the return movement the springs 36 are again additionally compressed. As a consequence, any tendency for the moving contacts of either contact set of bounce as they engage their complementary fixed contacts, is minimised.

Further, since the moving contacts of the normally closed contact set abut the complementary fixed contacts before the contact carrier and armature assembly terminates its plunger-initiated movement, the head member 3, acting through the said cont-acts and the compressed springs 36, impose a load of a preselected value upon the said assembly and this load (interalia) determines the speed at which the assembly is attracted towards the magnet against the action of the spring-loaded plungers, when the coil is energized. To ensure that an identical, or substantially identical, load is imposed upon the assembly when, after dismantling the spring clips 44, the head member is removed so that the original contact arrangement is substituted by a normally open contact arrangement only, means such as a bowed spring 60, see FIGURE 4, may be assembled to and lengthwise of the upper end of the gap 34 in the partitions 27 so that the said spring is abutted by the upper edge of the traverse 28 before the said assembly terminates its plunger-initiated movement; for example, the bowed spring may be pro- The head member is retained upon the partitions of i the arc chamber by lateral spring clips 44 having hooked ends which respectively engage holes 2 in the outermost partitions of the chamber and recesses 3 in the upper edge of the stem of the head member, and is located relatively to the said chamber by the engagement of projections 45 from the upper edges of the said outermost partitions 27, is compiementary recesses 42 in the lower edges of the outermost partitions 42.

The assembly consisting of the contact carrier 28 and armature 29 is urged away from the base 1, by a pair of spring-loaded plungers 54 mounted within diagonally opposite corners of the said base, so that when the circuit of the coil 18 is open, the said contact carrier and armature assembly is driven by the plungersinto abutment with the internal surface of the crown of the arc chamber, the moving contacts 37, 38, of the normally open set of contacts are disengaged from their com plementary fixed contacts 31, while the moving contacts 39, 40 are engaged with the complementary fixed contacts 41 of the normally closed set of contacts. When the coil circuit is closed, the coil is energized and the armature is attracted to the magnet core 14 so that the :said assembly is pulled downwardly toward the core Within the arc chamber and base against the action :of the spring biased plungers, the normally open set of contacts is closed, and the normally closed set of contacts is opened.

The stroke of the contact carrier and armature assembly is such that when the armature is attracted to g the m-agnet,'the moving contacts of the normally open set engage their complementary fixed contacts before the magnet-initiated movement of the assembly is completed so that during the final stage of the said movement, the

vided with hooked ends which are adapted to engage the holes 2 to retain the spring, convex face downwards, upon and between the outermost partitions 27. By loading the contact carrier and armature assembly in this manner, the speed at which the assembly is attracted towards the magnet is the same, or substantially the same, irrespectively of whether the relay is provided with both a normally open and a normally closed contact arrangement, or a normally open contact arrangement only.

The forms of the invention here described and illustrated are presented merely as examples of how the invention may be embodided and applied. Other forms, embodiments and applications of the invention, coming within the proper scope of the appended claims, will, of course suggest themselves to those skilled in this particular electrical field.

I claim: I 1. An electric relay adaptable to either a combined normally open and a normally closed contact arrangement or a normally open contact arrangement only, said relay comprising a single coil, an arc chamber, a first member adapted to be detachably secured to said chamber, a first set of contacts fixed on said chamber, a seocnd set of contacts fixed on said member, a third set of contacts, a contact carrier for moving said third set of contacts between said first and second sets of contacts, said first member cooperating with said coil to impose a first predetermined load on said carrier in such combined open and closed arrangement between said first, second and third sets of contacts, and a second member detachably secured to said chamber, said second member cooperating with said coil to impose a second predetermined load on said carrier corresponding to said first load in such open contact arrangement only between said first and third sets of contacts when said second member is substituted for said first member on said chamber.

2. An electric relay comprising a box-like base, a magnet, a coil and an armature housed in said base, an

arc chamber superimposed on said base, a contact carrier assembled to said armature, said carrier being disposed within said chamber and provided with an end projecting rearwardly thereof, a member adapted to be detachably assembled to said chamber, said member cooperating with said coil to impose a predetermined load on said carrier, fixed contacts disposed on said chamber and on said member, movable contacts disposed on said carrier for engagement with said fixed contacts in a combined normally open and a normally closed arangement therewith, and a non-contact means detachably assembled to said chamber, said means cooperating with said coil to impose a substantially identical load on said carrier as said member when substituted therefor, said means changing such combined open and closed arrangement to a normally open contact arrangement only.

3. An electric relay acording to claim 1 wherein said carrier is provided with apertures therein, two contact strips extend through each of said apertures beyond opposite sides of said carrier, a compressed spring is disposed within each of said apertures to urge said strips apart toward said first and second set of fixed contacts, said strips and said springs transmitting said first predetermined load from said member to said carrier.

4. An electric relay according to claim 1 wherein said second member comprises a bow spring, and said contact carrier abuts said bow spring when said relay is operated to re-open said normally open contacts.

5. An electric relay according to claim 1 wherein said first member is assembled to said are chamber externally thereof, said first set of fixed contacts being disposed externally of said chamber in spaced relationship from said corresponding second set of fixed contacts.

6. An electric relay according to claim 1 wherein said third set of contacts comprises pairs of movable contacts, each of said pairs being disposed between said first and said second sets of fixed contacts, and a stressed spring is disposed between each of said pairs to urge each movable contact apart, said spring being additionally stressed when either said normally closed contacts or said normally open contacts are closed.

7. An electric relay according to claim 6 wherein said carrier is formed with apertures therein, each of said pairs of movable contacts being disposed on a contact strip, two contact strips extending through each of said apertures beyond opposite sides of said carrier, and each of said stressed springs is disposed in one of said apertures to ur e said stri s a art, said stri s and said s rin s trans- P mitting said predetermined load from said second member to said carrier.

8. An electric relay according to claim 2 wherein said detachable member is externally assembled to said are chamber, a first set of said fixed contacts is disposed externally of said chamber in corresponding spaced relationship to a second set of said fixed contacts, pairs of said movable contacts disposed on said carrier between said first and second sets of fixed contacts, a stressed spring disposed between each of said pairs to urge said movable contacts apart, said spring being additionally stressed when either said normally closed contacts or said normally open contacts are closed.

9. An electric relay according to claim 8 wherein said carrier is formed with apertures therein, each of said pairs of movable contacts being disposed on a contact strip, two contact strips extending through each of said apertures beyond opposite sides of said carrier, and each of said stressed springs is disposed in one of said apertures to urge said strips apart, said strips and said springs transmitting said pretermined force from said detachable member to said carrier.

Reierences (Iited by the Examiner UNITED STATES PATENTS 2,162,126 6/39 Shaw 200-98 2,798,917 7/57 Hendricks et al. ZOO-98 2,881,284 4/59 Mekelburg 20098 2,919,327 12/59 Kuhn et al 200-104 2,921,166 1/60 Few et al. 200104 2,985,736 5/61 Coker et al. 200104 3,099,730 7/ 63 Tateishi ZOO- 104 3,109,905 11/63 Marquis 200166 3,129,304 4/64 Hyink et al. 200166 BERNARD A. GILHEANY, Primary Examiner.

MAX L. LEVY, ROBERT K. SCHAEFER, Examiners. 

1. AN ELECTRIC RELAY ADAPTABLE TO EITHER A COMBINED NORMALLY OPEN AND A NORMALLY CLOSED CONTACT ARRANGEMENT OR A NORMALLY OPEN CONTACT ARRANGEMENT ONLY, SAID RELAY COMPRISING A SINGLE COIL, AN ARC CHAMBER, A FIRST MEMBER ADAPTED TO BE DETACHABLY SECURED TO SAID CHAMBER, A FIRST SET OF CONTACTS FIXED ON SAID CHAMBER, A SECOND SET OF CONTACT CARRIER FOR MOVING SAID THIRD SET OF CONTACTS, A CONTACT CARRIED FOR MOVING SAID THIRD SET OF CONTACTS BETWEEN SAID FIRST AND SECOND SETS OF CONTACTS, SAID FIRST MEMBER COOPERATING WITH SAID COIL TO IMPOSE A FIRST PREDETERMINED LOAD ON SAID CARRIER IN SUCH COMBINED OPEN AND CLOSED ARRANGEMENT BETWEEN SAID FIRST, SECOND AND THIRD SETS OF CONTACTS AND A SECOND MEMBER DETACHABLY SECURED TO SAID CHAMBER SAID SECOND MEMBER COOPERATING WITH SAID COIL TO IMPOSE A SECOND PREDETEMINED LOAD ON SAID CARRIER CORRESPONDING TO SAID FIRST LOAD IN SUCH OPEN CONTACT ARRANGEMENT ONLY BETWEEN SAID FIRST AND THIRD SETS OF CONTACTS WHEN SAID SECOND MEMBER IS SUBSTITUTED FOR SAID FIRST MEMBER ON SAID CHAMBER. 